At sunset, a Customs and Border Patrol agent places floodlights along a levee that ties into a segment of border fence in Hidalgo, Texas.

State and national leaders, including Gov. Greg Abbott, said more resources should be devoted to border security following the death of a U.S. Border Patrol agent Sunday.

The agent died from injuries sustained while he was on patrol in southwest Texas, U.S. Customs and Border Protection said Sunday in a news release, offering sparse details. His partner was injured and was hospitalized in serious condition.

Rogelio Martinez and his partner – still unnamed – were “responding to activity while on patrol near Interstate 10,” about 100 miles east of El Paso, the agency’s release said. “Agent Martinez’s partner reported that they were both injured and in need of assistance. Responding agents provided immediate medical care, and transported both agents to a local hospital.”

Martinez, 36, died from his injuries. He had been a Border Patrol agent since 2013, and was from El Paso, according to news reports.

Officials on Sunday did not say what incident the pair were responding to. But Abbott called the incident “an attack” on Twitter, and politicians were quick to say more resources should go to border security.

“Our prayers are with the families of this Border Patrol Agent who was killed & the other who was injured in this attack in Texas,” Abbott said in a message posted to Twitter. “Our resources must be increased to prevent these attacks in the future.”

President Donald Trump, also responding on Twitter, made a renewed call for a wall along the U.S.-Mexico border.”We will seek out and bring to justice those responsible. We will, and must, build the Wall!” his tweet reads, in part.

In a statement Sunday, U.S. Sen. Ted Cruz wrote: “This is a stark reminder of the ongoing threat that an [unsecured] border poses to the safety of our communities and those charged with defending them.” He offered condolences and prayers and said, “I remain fully committed to working with the Border Patrol to provide them with all the resources they need to safeguard our nation.”

Jeanette Harper, with the Federal Bureau of Investigation’s El Paso office, toldthe San Antonio Express-News that the two agents had not been shot.

“They were not fired upon,” Harper said. “There are so many different agencies working together that we need to come together and develop a timeline.” She said more information would be released Monday.

Border Patrol agents and the Culberson County Sheriff’s Department secured the scene, according to the agency’s Sunday release, and the area was searched for potential suspects and witnesses.

In an email, a Border Protection spokesperson said the FBI is currently leading the investigation. The Sunday release said the local sheriff’s department, Office of Inspector General, and CBP’s Office of Professional Responsibility were also investigating the incident.

Both agents were assigned to the Big Bend Sector of the Border Patrol, a region that spans parts of Texas and Oklahoma.